Relay



Janc 12 9 w26., l 569 593 P. K. VAN DER STEER 9 RELAY Filed August 29, 1921 WITNEssEs: 5 E mvENToR Ww. Per/'us K/aas Van der .Sfar/z BY mim" Patented Jan. 12, 1926 UNITED STATES PATENT QFEICE.

PETRUS KLAAS VAN DER STEER, 0F FRANKFORT-ON-THE-MAIN, GERMANY, ASSIGNOR,

BY MESNE ASSIGNMENTS, TO WESTENGHOUSE ELECTRIC @t MANUFACTURING- COM- `PAN'Y, A CORPORATION 0F PENNSYLVANIA.

RELAY.

Application filed August 29, 1921.

To all whom t may concern:

. Be it lrnown that I, PETRUS KLAAs VAN DER STEER, a subject of the Queen of the Netherlands, residing at Frankfort-onthe- Main, Hanatuerlan'dstrasse 152/158, Germany, have invented certain new and uscful Improvements in Relays (for which I have led applicationsl in Germany Sept. 25, 1917; Aug. 8, 1919; and Jan. 26, 1920), of which the following is a specification.

My invention relates to relays and particularly to relays of the induction type.

The object of my invention is to provide a selective relay for protective purposes that shall be adapted for use in a complicated net-work which requires that certain relays operate before others in case abnormal conditions obtain in the system.

hen a short-circuit occurs in a power distribution'net-work, it is desirable to have the relays nearest the fault operate first vto trip the associated circuit-breakers, in order that the defective feeder or apparatus may be isolated with a minimum disconnection of operative feeders. It has been proposed to accomplish this by the use of relays that depend for their speed of operation upon the voltage existing' at the relay, for it will be apparent that the line voltage varies from Zero at the short-'circuit to the generator voltage at the substation.

In accordance with my invention a relay is provided that is adapted to distinguish between small differences of voltage in order to operate selectively to isolate a defective feeder.

For a better understanc'ling of my invention, reference may be had to the accompanying drawings wherein Figure 1 is a diagrammatic view of a relay embodying my invention;

Fig. 2 is a side view showing the magneltizable core element and disc of the induc tion-motor mechanism; and

Figs. 3 and it are views oit' modiications of the relay.

Referring to l? 1, the relay comprises a weight 1 adapted to rotate a dise 2 of the induction-motor mechanism in a clockwise direction. Acore element.lhaving a voltage winding 3 thereon is disposed adjacent the disc 2. An overload relay t is connected in series with the line circuit 18 and controls the operation of the induction-mo- Serial No. 496,673.

tor mechanism by means of an electro-inagnet 5 having a pivoted armature G. The

armature G controls contacts 7 in the circuit of the coil 3 and also operates ay detent 8 carried upon the pivoted bar 9.

A shading coil 1() is located upon one of the poles of the core element 17 and is noi-` mally short-circuited by the contacts 11. A second shading coil 12 is also arranged upon the core element 1.7 and is short-circuited, when the relay operates, by the contacts 13. An adjusting resistance 14 is connected `in series with the coil 12 to facilitate adjustment of the time of operation of the relay. The coils 3, 10 and 12 are so arranged upon the core element 17 that a counterclocliwise torque is exerted upon the disc 2 when the coil 3 is energized and either of the shading coils is short-circuited.

Upon the occurrence of a short-circuit in the line, the overload relay et operates and closes the circuit of the electro-magnet 5. rThe electro-magnet 5 attracts its armature 6, thereby closing the contacts 7 and removing the dctent 8 from `engagement with the disc 2, so that the disc is free to rotate. The weight 1 rotates the disc 2 in the clockwise direction. rThe rate of rotation of the disc 2 depends upon the restraining force produced by the induction-motor torque, since the coils 3 and 12 produce a countercloclrwise torque upon the disc 2. Obviously this torque depends largely upon the current through the coil 3 which depends, in turn, upon the line voltage. During a short-circuit, this is of course dependent upon the distance of the relay from the fault.

Accordingly where several relays are cmployed at different points in a net-work, the time of operation of each relay depends upon its distance from the fault. Since the voltage is lowest at the short-circuit, the nearest relay will have less restraining torque upon the disc 2 and this disc will be. rotated faster than that of any other relay. After the disc is rotated a predetermined distance, the weight 1 stri-lies `the contacts 15, closing the circuit of a trip coil 19, there by opening the circuit breaker 2O associatedl with the relay and clearing the fault from the system.

rThe relay is adapted to reset to normal in case the overload relay 4 opens its contacts either by reason of the fact that the overload has ceased or that some other relay has ope ated. Upon the restoration of the armature 6 the contacts 1l are closed and a counter-clocl-nvise torque is produced by the coils 3 and l0. This torque returns the disc 2 to its normal position, Winding up the Weight l until it strikes the stop 2l and unlatches the bar 9. The bar 9 returns .to normal and latches the disc 2 in its normal position. The contacts 7 are noiv opened, thereby stopping the induction-motor mechanism.

In the modification shown in Figs. 3 and 4L, the relay is constructed like a reversing relay. lVhen the overload relay 5 operates, it connects the coil 3 with the line circuit through the contacts 7. Thus the operation setting torque.' After the overload has been relieved, the relay 5 restores and shortcircuits the coil 8 and the relay mechanism is reset to normal. As before, l5 designates the tripping contacts of the circuit breaker.

I have found that the sensitivity of selective relays of this type may be increased by rising a series resistance of high positive temperature-coefiicient. This resistance may be connected as shown at 16 in Fig. 4, so that it is in the circuit of the coil 3 only When the auxiliary relay 5 is operated and closes the contacts 7. By using a series resistance having a high positive temperaturecoeflicient, the relay becomes sensitive to smaller differences of voltage. In order to obtain the advantage of the temperaturecoetficient during the operation of the relay it is necessary to connect it in circuit as shown only during such operation.

I claim l. A relay comprising, in combination, a disc, mechanical means tending to rotate the same in one direction, a voltage responsive coil located in inductive relation to said disc, a second coil inductively related to said voltage coil adapted to produce in conjunction with said voltage coil a shifting magnetic lield tending' to rotate said disc in the opposite direction, detent holding said disc in normal position, a switch in the circuit ot' said voltage coil closed when said detent is released trom engagement With said disc, electro-responsive means tor releasing said detent, and contacts operated upon a predetern'iined travel of said disc.

A relay comprising, in combination, a. metallic non-magnetic member, rotatably mounted, mechanical means tending to rotate said member in one direction, a detent holding said member in normal. position` a voltage responsive coil adapted to bc connected across the line circuit located in inductive relation to said member, a second coil inductively related to said voltage responsive coil adapted to produce in conjunction With said voltage responsive coil a shifting magnetic field operating to rotate said member against the action of said mechanical means, means for releasing said detent and connecting said voltage coil across the line, means tor holding said detent in released position and the circuit of said voltage responsive coil closed, and means operated by said member to release said latch when said member resumes normal position.

3. In combination, a line circuit, a relay in the line circuit actuated When the current therein exceeds a predetermined value, a circuit breaker .tor -opening the line circuit, a timing mechanism adapted to actuate said circuit breaker after a predetermined movement when released, a detent holding said timing mechanism in normal position, means actuated by said relay When energized to release said detent, motor means for returning said timing mechanism to normal position, and means operated by said timing mechanism upon reaching normal position to operate said detent.

4t. A relay comprising, in combination, an induction motor mechanism adapted to open the line circuit after a predetermined movement from normal position, means for setting said timing mechanism in operation controlled by the current in the line, and means for resetting said mechanism to normal, said last-named means also governing the rate of movement of said mechanism in accordance with the voltage of the line at the point Where said relay is located.

5. A relay comprising contacts, a rotatable disc having a normal' position, a detent for said disc, mechanical means for rotating said disc in one direction to operate said contacts, means for resetting the disc to normal comprising a magnetizable core member having windings thereon, and means including one oif said windings for producing a. re.v straining torque during the operation oi said relay.

6. A relay comprising contacts, a rotatable disc for actuating the same, mechanical means for driving the disc to operate said contacts, and means including a magnetizable core member having a winding thereon for restraining the contact-operating movement of said disc and for resetting the disc to normal. i

In testimony vfhereoil l alix my signature.

PETRUS vI{ Q AAS van Drin STER-R 

